METHOD OF MANUFACTURING HYPERFINE-GRAINED STEEL

摘要

PURPOSE: A method is provided to obtain a steel having a hyper fine-grained structure with a ferrite having an average particle diameter of 3 micrometer or less at a low deformation resistance, low draft percentage and low cooling speed. CONSTITUTION: A method comprises the steps of transforming a material into austenite by heating the material to a temperature of Ac3 point or higher after performing melting fusion process, performing a compression process at a temperature of Ae3 point or lower, Ar3-150°C or 550°C or higher, and a draft percentage of 50% or higher, and cooling the resultant material.